If there's a theme prevalent throughout the last round of the MLS postseason, it's that proficiency off of dead-ball situations has been vital to staying alive.

Out of the four remaining teams, only Real Salt Lake has yet to benefit from a set piece during its playoff run. As for the others? It's been a set-piece bonanza.

Free kicks or penalties have accounted for seven of the 11 goals scored by Los Angeles, Houston and Sporting Kansas City, who have been riding the service of David Beckham, Brad Davis and Graham Zusi, respectively, to results all season.

And even though RSL, which boasts free-kick taker Javier Morales, didn't score off a set piece during its conference semifinal triumph over Seattle, the club successfully defended 10 Sounders corner kicks in the second leg, preventing Seattle from completing a would-be historic comeback with an organized effort despite missing centerbacks Jamison Olave and Nat Borchers.

The importance of converting and defending set pieces can't be stressed enough going forward after the last batch of results.

Out of the Los Angeles Galaxy's three goals against New York, only one came in the run of play, and even then it was set up by a Beckham cross. New York's set-piece defending, which has been a weakness all season long, played a big factor Thursday night in allowing Mike Magee to have a free header off a Beckham corner kick just before halftime for the series-altering tally.

The Houston Dynamo, perhaps the most potent team in the league off set pieces, tallied two of its three goals in its series against Philadelphia off free kicks taken by Davis, its left-footed maestro. Like New York, Philadelphia's Achilles' heel this season was defending set pieces, and the club's zone-marking approach gifted Brian Ching a free look for a dagger of a header in Houston's second-leg victory.

"Sometimes it can win a game for you," Houston coach Dom Kinnear said. "Brad just puts it in great positions."

Sporting Kansas City rolled to a 4-0 aggregate win over defending champion Colorado, but only one of those goals came in the run of play. Teal Bunbury tallied on a counterattack and from the penalty spot in the opening leg, and the club managed both of its goals in the second leg off free kicks taken by Zusi.

"It's one thing to have guys that are good in the air and are big bodies and get in good spots, but what really makes a team good on set pieces is having someone who can consistently put the ball where you want it to be," Sporting Kansas City coach Peter Vermes said. "There's no doubt that Graham has emerged as that guy for our team. At the same time he's a guy who can strike within shooting distance. It's been a big part to our game."

Fouls and physical play in the attacking third will undoubtedly play a huge role in the conference finals, as the four teams remaining boast some of the best dead-ball strikers in the game. With two pairs of evenly matched sides going up against each other in a one-game, winner-take-all setting, the ability to convert — and defend — outside of the run of play may very well determine which teams advance to MLS Cup.

"Obviously (the Dynamo's) set pieces have been a big part of their game. One reason is due to good service but their guys to a good job and are aggressive," Vermes said. "At the end of the day you have assignments. It's much like an American football game. This is your guy. You have to take him out of the game or block him. It's the same thing in set peices in our game as well. We have to be conscious and focused on those."